21688465365 has 128 divisors (see below), whose sum is σ = 47466086400. Its totient is φ = 9177442560.

The previous prime is 21688465361. The next prime is 21688465367. The reversal of 21688465365 is 56356488612.

21688465365 is a `hidden beast` number, since 2 + 1 + 68 + 8 + 46 + 536 + 5 = 666.

It is not a de Polignac number, because 21688465365 - 2² = 21688465361 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21688465361) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 657691 + ... + 689879.

It is an arithmetic number, because the mean of its divisors is an integer number (370828800).

Almost surely, 2^21688465365 is an apocalyptic number.

It is an amenable number.

21688465365 is an abundant number, since it is smaller than the sum of its proper divisors (25777621035).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21688465365 is a wasteful number, since it uses less digits than its factorization.

21688465365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32264 (or 32258 counting only the distinct ones).

The product of its digits is 8294400, while the sum is 54.

The spelling of 21688465365 in words is "twenty-one billion, six hundred eighty-eight million, four hundred sixty-five thousand, three hundred sixty-five".